/*
 * Copyright 2002-2008 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.ctrip.cap.common.exception;

import java.io.PrintWriter;
import java.io.StringWriter;

/**
 * Helper class for implementing exception classes which are capable of holding
 * nested exceptions. Necessary because we can't share a base class among
 * different exception types.
 *
 * <p>
 * Mainly for use within the framework.
 *
 * @author Juergen Hoeller
 * @since 2.0
 */
public abstract class NestedExceptionUtils {

	/**
	 * Build a message for the given base message and root cause.
	 * 
	 * @param message
	 *            the base message
	 * @param cause
	 *            the root cause
	 * @return the full exception message
	 */
	public static String buildMessage(String message, Throwable cause) {
		if (cause != null) {
			StringBuilder sb = new StringBuilder();
			if (message != null) {
				sb.append(message).append("; ");
			}
			sb.append("nested exception is ").append(cause);
			return sb.toString();
		} else {
			return message;
		}
	}

	/**
	 * full exception stack
	 * 
	 * @param e
	 * @return
	 */
	public static String buildStackTrace(Throwable e) {
		StringWriter writer = new StringWriter();
		PrintWriter printWriter = new PrintWriter(writer);
		e.printStackTrace(printWriter);
		printWriter.flush();

		return writer.toString();
	}

}
